1. Technical Field
This invention relates generally to a device for providing access to a target site within the body of a patient, and more particularly, to a medical device for providing percutaneous access to a patient's air passageway.
2. Background Information
The restoration of an adequate air passageway is the first critical step in maintaining the ability of a seriously ill or injured patient to breathe, or in performing resuscitation on a patient unable to breathe. Endotracheal intubation (the insertion of a breathing tube through the nostrils or mouth and into the trachea itself) is the preferred method for establishing an air passageway when the trachea, nostrils and/or mouth are free of obstruction. When such obstruction is present, however, endotracheal intubation may not be possible. In such instances, airflow must be established through an alternate passageway in the body of the patient.
The most direct way to provide an air passageway under these circumstances is to form an opening in the tracheal wall, and once formed, to maintain the opening by positioning a tracheostomy tube through the opening. Conventional tracheostomy tubes generally comprise a curved tubular member having an open distal end extending into the trachea, and an inflatable cuff to provide a seal between the tracheal wall and the tracheostomy tube.
Several methods and devices are known for forming or enlarging an opening in a tracheal wall. Each method is subject to its own advantages and drawbacks. For example, tracheostomy and cricothyrotomy procedures have been performed by using a scalpel to make a rather large incision in the neck for insertion of the tracheostomy tube. Such procedures entail a high degree of surgical skill to perform successfully, particularly since it is vital to locate and avoid unintentional severing of the blood vessels in the area. These procedures can even require the surgeon to cut through several blood vessels and ligate (tie) them to the trachea, in order to achieve an adequately large opening. The length of time needed to perform these procedures (often, on the order of half an hour) is poorly suited for emergency treatment, when prompt restoration of the air passageway is critical. Moreover, the use of a scalpel to fully form a relatively large opening may cause undue trauma to the tissues surrounding the opening, and can result in the formation of an unduly large or oversized opening in the soft tissue of the neck.
To minimize such trauma, it is desirable to initially incise only a small opening, and thereafter enlarge the opening with further dilation. For example, one technique for dilating an opening includes the use of a wire guide to facilitate the introduction of a dilator into the trachea. This technique involves the insertion of a needle and an over-the-needle catheter into the trachea. The needle is removed and the catheter replaced with a wire guide. A tapered, elongated, tubular dilator is positioned over the wire guide and introduced into the trachea. Even though intended to be performed in an emergency situation, this technique entails the sequential manipulation of several devices by the physician, which is time consuming and complicates the procedure.
Another procedure eliminates the use of the catheter and involves placing a wire guide through the needle itself. The opening formed by the needle is then dilated by the use of a device having a handle and a nose, the nose extending laterally from the axis of the handle. The nose has two jaws that spread apart for separating the tissue surrounding the opening, and the device is introduced into the trachea by positioning the elongated, tapered nose over the wire guide. While this type of device offers more powerful dilation than is possible with elongated tubular dilators, a problem with the device is that the unguarded nose must be inserted into the trachea with precision, and must be manipulated at an angle, in order to avoid perforating the posterior tracheal wall.
Another prior art technique for dilating an opening is the use of a tapered, elongated, tubular dilator, or a series of tapered dilators having increasingly larger diameters. Although such dilators are effective for forming a suitably-sized opening in the tracheal wall, each dilator presents a pointed distal end to the posterior tracheal wall when introduced into the trachea. The risk of injury to the trachea is compounded by the toughness of the tracheal membrane, which resists the introduction of medical devices. Introducing these elongated dilators may require the application of considerable force. Although a hydrophilic coating may be applied to the dilator to reduce the amount of force required to insert the dilator, a physician must still exert a downward force to push the dilator into the trachea, and yet avoid puncturing the posterior tracheal wall.
Another prior art technique involves the use of a balloon catheter to radially expand an opening formed in the tracheal wall. This device permits the enlargement of an opening without risk of perforating the rear of the trachea by providing a polymeric inflatable balloon at the distal end of the catheter. The device is inserted over a previously positioned wire guide such that the uninflated balloon spans the tracheal wall. The balloon is thereafter inflated to radially dilate the opening in the tracheal wall.
Although the recited devices may be effective for dilating an opening, such methods may be complex, and often require several procedural steps to carry out the procedure. In addition, numerous separate components must often be manipulated to carry out the procedure. This increases the time, complexity, and cost of the procedure.
It would be desirable to provide a device for use in gaining access to a target site of the patient, such as the patient's airway, that enables the access procedure to be carried out in a relatively short period of time, and that does not require the use of numerous individual components for carrying out the procedure.